events-backend: added initial DB events store

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
2024-05-24 00:48:53 +02:00
parent d32c8ff2e3
commit 93cb484bcd
7 changed files with 316 additions and 11 deletions
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2024 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// @ts-check
+
+/**
+ * @param { import("knex").Knex } knex
+ * @returns { Promise<void> }
+ */
+exports.up = async function up(knex) {
+  // The event bus only supports PostgresSQL
+  if (knex.client.config.client === 'pg') {
+    await knex.schema.createTable('event_bus_events', table => {
+      table.comment('Events published to the events bus');
+      table
+        .bigIncrements('id')
+        .primary()
+        .comment('The unique ID of this event');
+      table
+        .dateTime('created_at')
+        .defaultTo(knex.fn.now())
+        .notNullable()
+        .comment('The time that the event was created');
+      table.text('topic').notNullable().comment('The topic of the event');
+      table
+        .text('data_json')
+        .notNullable()
+        .comment('The payload data of this event');
+      table
+        .specificType('consumed_by', 'text ARRAY')
+        .comment(
+          'The IDs of the subscribers that have already consumed this event',
+        );
+    });
+
+    await knex.schema.createTable('event_bus_subscriptions', table => {
+      table.comment('Subscriptions to the event bus');
+      table
+        .string('id')
+        .primary()
+        .notNullable()
+        .comment('The unique ID of this particular subscription');
+      table
+        .dateTime('created_at')
+        .defaultTo(knex.fn.now())
+        .notNullable()
+        .comment('The time that the subscription was created');
+      table
+        .dateTime('updated_at')
+        .defaultTo(knex.fn.now())
+        .notNullable()
+        .comment('The time that the subscription was last updated');
+      table
+        .bigInteger('read_until')
+        .notNullable()
+        .comment(
+          'The sequence counter until which the subscription has read events',
+        );
+      table
+        .specificType('topics', 'text ARRAY')
+        .comment('The topics that this subscriber is interested in');
+    });
+  }
+};
+
+/**
+ * @param { import("knex").Knex } knex
+ * @returns { Promise<void> }
+ */
+exports.down = async function down(knex) {
+  if (knex.client.config.client === 'pg') {
+    await knex.schema.dropTable('events');
+  }
+};